a = 10
b = 20
c = 30
print(a < b < c)  # 等价于print(a < b and b < c)
print(a < b and b > c)
print(a > b or b > c)
print(not a < b)

# 逻辑运算符总是遵守：短路求值
# 比如对于and来说，如果左侧表达式为False，则整体表达式一定为False
# 那么此时右侧表达式不必求值，比如：
print(a > b and 10 / 0 == 1)
print(a < b or 10 / 0 == 1)